This invention relates to a rolling element bearing having a rolling element chamber sealed by elastic gaskets secured to one of the races.
Dependable seals for rolling element bearings are an essential prerequisite for long service life of the bearing, and consequently of a machine or a motor vehicle using the bearings. Furthermore, sealed bearings simplify design because, in general, no additional packing is required, and the lubricant fill suffices for the life of the bearing. The installation space required for such sealed rolling bearings is small, assembly is problem-free, and the hazard of fouling during installation or in service is nonexistent.
In a known type of double-row tapered roller bearing (British Pat. No. 1,191,685), the inner bearing space is completely closed off laterally from the outside by a seal housing. This lateral seal housing is secured in an annular groove in the outer race, and a corrugated sealing ring is mounted in the groove. The sealing lips of the sealing ring slide on a spacer sleeve mounted on a shaft. For air supply to and exhaust from the rolling element chamber, passages are provided in the seal housing. These passages are closed by plastic inserts overlapping on the outside of the sealing ring. These overlaps may alternatively be formed integrally with the corrugated sealing ring. The arrangement of through-slits in the outer overlap is intended not only to vent, but also to aerate the rolling element chamber. Such through-slits, however, venting and aerating the rolling element chamber, are not universally useful, since they present no barrier to dirt entering the chamber from the outside. Such dirt entering the rolling element chamber from the outside substantially shortens the life of the bearing. Severe fouling may even result in destruction of the bearing.
The present invention provides a rolling element bearing having a rolling element chamber closed off externally by means of elastic gaskets, that permit firstly an excess pressure equalization of the rolling element chamber under operating condition and secondly ensure a dependable seal both externally and internally.
The sealing arrangement according to the present invention renders it possible not only to prevent entry of dirt into the rolling element chamber, but also to permit excess pressure generated by heating in the rolling element chamber while the bearing is in operation, and consequently trapped there, to be vented promptly to the outside by an elastically yielding opening of a weak spot in the sealing ring, thus ensuring a pressure equalization of the chamber in case of excess pressure. This "weak spot" in the gasket springs back like a diaphragm to is initial position after the excess pressure escapes, thus restoring the seal between the rolling element chamber and the outside. Since excess pressure can blow off only from the rolling element chamber to the outside, any penetration of dirt into the rolling element chamber from the outside is precluded. The brief opening and closing of the weak spot also prevents lubricant from being lost by leakage from the rolling element chamber. This means that the lifetime lubricant fill will be kept in the bearing, thus ensuring a long service life for the bearing.